the "energy_units" above does not give you energy consumption yet. It is a conversion constant. You need to multiply readings from additional PKG_ENERGY_STATUS MSR by "energy_units" to get the current value of the energy counter in Joules. The difference between two PKG_ENERGY_STATUS readings gives you energy consumption between the readings. Be aware: The width of PKG_ENERGY_STATUS is just 32 bit, so it may overflow, but you can handle it knowing the that the counter is 32 bit and if overflown only once. The Intel Software Development Manual has a few chapters describing these and other details of RAPL including DRAM RAPL.